Sofa



FIG. 1 is a perspective view of a first embodiment of a sofa showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a perspective view of a second embodiment of a sofa showing my new design;

FIG. 4 is a front elevation view thereof.

FIG. 5 is a perspective view of a third embodiment of a sofa showing my new design; and,

FIG. 6 is a front elevation view thereof. 

CLAIM I claim the ornamental design for a sofa, as shown and described. 